ABB S800 I/O NZ | AI810 DI810 DI814 AO810V2 TU830V1 MTU

ABB S800 and S800L Process I/O

ABB / S800 I/O

The I/O modules can be changed live. The termination units cannot, and pulling one kills every station downstream of it.

S800 I/O is the ABB distributed process I/O system, used with AC 800M, Advant and 800xA, and with third-party controllers over fieldbus. Widely installed in New Zealand water treatment, dairy and process plant.

Modules hot swap. Termination units do not.

The most important operational fact about S800, and it runs opposite to the AC500 platform where nothing may be changed live.

Part	Live replacement
Analog input modules	Permitted. Turning the locking mechanism deactivates the module
Analog output modules	Permitted, but the process device may need setting to a safe state manually first
Digital input modules	Permitted
Digital output modules	Permitted
DP820 and DP840 pulse counters	Permitted, safe state may need setting first
All MTUs	Cannot be replaced or repaired with power applied

And removing an MTU takes out everything after it

ABB is explicit, and this is the detail that turns a small job into an outage.

Disconnecting an MTU breaks the ModuleBus communications bus and removes power to the MTUs that follow it.

Worse, on a middle station: MTUs mounted between the ModuleBus master or cluster modem and the number 12 MTU need the preceding or following MTUs physically moved in order to disconnect the ModuleBus connector.

So replacing an MTU in the middle of a cluster means dropping everything downstream and shuffling neighbouring units. Plan that as an outage, not a live repair.

The good news is that MTUs rarely fail, because they are passive. The module is the part that fails, and the module can be changed live.

The MTU keying prevents the wrong module going in

A well-designed feature worth knowing about.

MTUs are mechanically keyed so an incorrect module cannot be installed. The TU810 uses two keys with six positions each, giving 36 unique configurations.

The keys have to be set correctly. A replacement MTU arrives and the keying must be configured to match the module that goes on it. Get that wrong and either the right module will not fit or the wrong one will.

Tell us which module the MTU is for and we will note the keying requirement.

Sink or source, and the 48 volt one

Three digital input modules that look almost identical and are not.

Module	Channels	Voltage	Type
DI810	16, in 2 groups of 8	24 V DC	Current sink
DI811	16, in 2 groups of 8	48 V DC	Current sink
DI814	16, in 2 groups of 8	24 V DC	Current source
DI818	32, in 2 groups of 16	24 V DC	Current sink

DI810 and DI814 are both 16 channel 24 V DC modules. One sinks and one sources. Same trap as Omron DT and DT1 on our CP series page. Fit the wrong one and no input reads.

And the DI811 is a 48 V module. One digit from the DI810 and twice the voltage.

Read the existing module rather than matching on channel count.

All three provide per-channel current limiting, EMC protection, an input state LED and optical isolation, with a voltage supervision input for each group of eight.

Analog input modules

Module	Specification
AI810	8 channels, 1 group, single ended with common return. 0(4) to 20 mA, 0(2) to 10 V, 12 bit
AI815	8 channels, single ended. 0(4) to 20 mA, 0(1) to 5 V, 12 bit, HART interface and transmitter power supply
AI820	4 channels, bipolar differential. Plus and minus 0(1) to 5 V, 0(2) to 10 V, 0(4) to 20 mA, 14 bit plus sign
AI825	4 channels, individually galvanically isolated, separate returns. Isolated bipolar, 14 bit plus sign
AI830A	8 channels RTD with wire-fault detection. Pt100, Ni100, Ni120, Cu10, resistance 0 to 400 ohm, 14 bit, 3-wire
AI835A	8 channels thermocouple with open circuit detection, 7 plus reference junction. Types B, C, D, E, J, K, L, N, R, S, T, U, minus 30 to 75 mV, 15 bit

Three distinctions worth understanding

AI810 is single ended with a common return; AI820 is differential. Differential inputs reject common mode noise between separately earthed field devices. If a signal was noisy and someone specified an AI820, substituting an AI810 brings the problem back.

AI825 goes further with individually isolated channels. That is for field devices at genuinely different potentials, and neither an AI810 nor an AI820 replaces it.

AI815 carries HART and supplies the transmitter. Replacing it with an AI810 loses both the HART communication and the loop power.

These four modules all read 4 to 20 mA and are not interchangeable.

Analog output

Module	Specification
AO810V2	8 channels with open circuit detection. 0(4) to 20 mA, 14 bit, maximum load 850 ohm, short circuit proof

The 850 ohm maximum load is the figure to check. A long cable run plus a positioner plus a series indicator can exceed it, and the symptom is an output that will not reach 20 mA.

Other analog outputs in the range include AO810, AO815, AO820, AO845, AO845A, AO890 and AO895.

The full module range

Type	Modules
Analog input	AI801, AI810, AI815, AI820, AI825, AI830, AI830A, AI835, AI835A, AI843, AI845, AI880, AI880A, AI890, AI893, AI895
Analog output	AO801, AO810, AO810V2, AO815, AO820, AO845, AO845A, AO890, AO895
Digital input	DI801, DI802, DI803, DI810, DI811, DI814, DI818, DI820, DI821, DI828, DI890
Digital input with sequence of events	DI825, DI830, DI831, DI840, DI880, DI885
Digital output	DO801, DO810, DO814, DO815, DO818, DO820, DO821, DO840, DO880
Pulse counter	DP820, DP840
Fieldbus interface	CI801, CI840

The SOE modules are worth identifying. DI825, DI830, DI831, DI840, DI880 and DI885 provide sequence of events time stamping. On a process plant that is how a trip is reconstructed afterwards, and a standard DI810 does not do it.

Module termination units

Confirmed article numbers

MTU	Article number	Channels	Voltage	Connection
TU830V1	3BSE013234R1	16	50 V	Terminal block
TU831V1	3BSE013235R1	8	250 V	Terminal block
TU833	3BSE038726R1	16	50 V	Crimp snap-in connector
TU834	3BSE040364R1	8		Terminal block, for shunt sticks

The 250 volt MTU is for the 250 volt modules

Important pairing. The TU831V1 at 250 V takes the DI820, DI821, DO820 and DO821 modules, which are the mains-voltage digital I/O.

The 50 V MTUs take everything else. You cannot put a 250 V module on a 50 V MTU, and the keying is there to stop you.

The TU834 is specifically for the AI880 and AI880A.

MTU types by feature

MTU	Description
TU810, TU810V1	Compact, 16 channel, 50 V. Three rows of terminals for field signals and process power
TU811, TU811V1	Compact, 8 channel. Three rows of terminals
TU812, TU812V1	Compact, 16 channel, 50 V, with 25 pin D-sub for field signals and process power
TU830V1, TU835V1, TU838, TU850	Screw terminals, power distribution and fuse
TU831V1, TU836V1, TU837V1, TU839, TU851	Screw terminals, power distribution and fuse
TU833	Spring-cage terminals, power distribution and fuse
TU834	Screw terminals for shunt sticks, TY80X
TU842, TU843	Screw terminals, horizontal and vertical mounting
TU844, TU845	Screw terminals with shunt sticks, horizontal and vertical
TU852, TU854	25 pin D-subs with shunt sticks, horizontal and vertical
TU805	For S800L DI801 and DO801, mounts directly on the module

The horizontal and vertical variants are different part numbers. TU842 and TU843 are the same MTU in two mounting orientations. Check which way your rack runs.

TU810 features

DIN rail mounting with secure latch
36 position mechanical keying
Horizontal or vertical mounting
ModuleBus distribution
Automatic address shifting
IP20 protection against contact
5 to 95 percent relative humidity
Pollution degree 2
ISA G3 corrosion protection
Hazardous location approved

ISA G3 corrosion protection matters in New Zealand. Coastal sites, wastewater plants and any location with hydrogen sulphide present will attack standard electronics. If your existing hardware is G3 rated, the replacement should be.

S800L, the compact variant

S800L uses a different arrangement: modules such as DI801, DO801 and AI801 with the TU805 terminal unit mounting directly onto the module rather than the module plugging into an MTU.

The TU805 is a 16 channel terminal unit enabling 2 and 3 wire connections on the DI801 or DO801.

S800L and S800 are not interchangeable. Different mechanical arrangement entirely.

Fieldbus interfaces

Module	Function
CI801	Fieldbus communication interface
CI840	Fieldbus communication interface, redundant capable

ABB notes that station-specific diagnostics appear in the CI801 or CI840 diagnosis control, and that AI895 and AO895 have their own HART diagnostics.

The DTM software provides module identification, dynamic values and diagnosis covering module missing, wrong module type and internal channel errors.

What to send us

The module type. AI810, DI814 and so on.

Whether you need the MTU as well. Usually you do not, since the module is what fails.

For an MTU, which module it carries, because that determines the keying and the voltage class.

The 3BSE article number if you have it.

Whether the site needs G3 corrosion protection.

What we can supply

The full S800 and S800L range. Analog and digital modules, SOE modules, MTUs in all connection types, CI fieldbus interfaces and accessories.

S800 is mature rather than current in many variants, so a good part of this is surplus and tested used. That is usually the fastest route on a process plant where the alternative is a system upgrade.

Hold spares for the modules you run. Because modules hot swap and MTUs do not, a spare module turns a fault into a five minute job. Without one it waits for an outage.

We buy S800 I/O

S800 modules hold real value to plants still running them. If you are upgrading a control system, do not scrap the I/O. See Sell To Us.

Send us your module list

One module or a full station. Tell us whether it is S800 or S800L, since the mechanical arrangement differs. Quotes in NZD including GST.

Request a quote

Industech is an independent supplier of new, surplus and used industrial automation equipment. We are not an authorised distributor of, approved by, sanctioned by, or affiliated with ABB Ltd. ABB, S800, Advant and 800xA are trademarks of ABB Ltd. HART is a trademark of the FieldComm Group. All trademarks, brand names and article numbers are the property of their respective owners and are used here for identification purposes only.