Universal digital input | IMDSI22 | ABB

Technical Specifications

The IMDSI22 Digital Input Module consists of a single printed circuit board that occupies one slot in a module mounting unit. It monitors two separate groups of eight digital inputs. Twelve inputs are isolated from each other; the remaining two pairs share common positive input lines. Two captive screws on the module faceplate secure it to the module mounting unit. Sixteen front panel LED status indicators (group A and group B) display the input status and provide aid in system test and diagnosis. The digital input module has three card edge connectors for external signals and power (P1, P2 and P3). P1 connects to common (ground) and +5 VDC power. P2 connects the module to the I/O expander bus to communicate with a controller. P3 inputs the digital signals using a cable connected to a termination unit. The terminal blocks (physical connection points) for field wiring are on the termination unit. 

Functional Operation

The IMDSI22 Digital Input Module is an interface used to bring 16 separate process field signals into the Symphony Enterprise Management and Control System. These digital inputs originate from field devices such as switches, relay contacts, and solenoids, and enter the module through connector P3. The input channels operate in either system-powered or externally powered configurations, depending on application requirements. Field wiring terminates at a compatible termination unit and connects to the module through a termination cable.

Each input channel contains a current limiter that restricts the input current, followed by an optocoupler that provides galvanic isolation between the field circuitry and the module logic. The input circuits provide 1500 VDC isolation between the field inputs and the internal logic. Twelve inputs are isolated from each other; the remaining two pairs (A7/A8 and B7/B8) share common positive input lines. The digital input high impedance provides additional passive protection from high energy transients of field digital inputs.

Output Control Logic

An output register holds the data that controls the outputs.The I/O expander bus interface writes control module data tothis register. This data, sent to the data selector, determinesthe output states (ON or OFF).Default data from the control module is sent to the default register. The control module configuration sets the default values(Function Code 128). The default register is reset to logic zerosduring power up to drive the outputs to a de-energized state.FC 128 in the control module configuration selects the outputvalues used to drive the output circuits in the event of a control module failure (time-out). If FC 128 is not defined, the outputs will go to a de-energized state during a time-out. Refer toBUS FAULT TIMER in this section for further explanation oftime-out. 

The default control logic block is a one bit latch register. Itsends a signal to the data selector block to select either thedefault register data or the output register data during atime-out (indicating a control module error). This signal isdependent on the control module configuration (FC 83 specification S2). The bus fault detector in the I/O expander businterface checks for a time-out condition. During a time-out, thedata selector block normally selects the default register data. Ifa hold option is selected in FC 83, the default control logic circuits send a logic 1 to override the data selector. It causes thedata selector to drive the outputs with the output register datainstead of default data to maintain the outputs at their currentvalues (hold)

Technical FAQ

Q: What distinguishes the IMDSI22 from the IMDSI13 and IMDSI14?
A: The IMDSI13 supports only 24 VDC inputs and the IMDSI14 supports only 48 VDC inputs, both being fixed-configuration modules, whereas the IMDSI22 is a universal module configurable via jumpers to accept 120 VAC, 24 VDC, 48 VDC, or 125 VDC inputs.

Q: Are all sixteen input channels on the IMDSI22 fully isolated from each other?
A: No. While the module provides 1500 VDC isolation between inputs and logic circuitry, only twelve inputs are isolated from each other; the remaining two pairs, specifically points A7/A8 and B7/B8, share common positive input lines and must therefore use the same contact voltage.

Q: How is the working voltage and AC/DC mode configured on the IMDSI22?
A: TConfiguration is performed through thirty-two jumpers on the module: odd-numbered jumpers (J1, J3, J5 through J31) select the working voltage, while even-numbered jumpers (J2, J4, J6 through J32) select AC or DC mode by strapping pins 1-2 for AC or pins 3-4 for DC.

Q: Do you supply brand-new, original parts or second-hand refurbished items?

A: Our stock consists of Original New items; all products undergo quality inspection to ensure they are fully functional.

Q: What guarantees are included with the shipment?
A: All items in stock are tested by engineers, packed in professional ESD packaging, and shipped via express logistics with a global delivery time of 24–48 hours.

Q: How long does global shipping take?
A: Stock items are typically dispatched within 24 hours. Shipments are sent via DHL or FedEx Express, taking approximately 3–5 days to reach Asia, 4–6 days to Europe and the Middle East, and usually arriving within a week in major industrial regions worldwide.

Q: If the model I need is not listed on the website, can I request a quote?
A: Yes. We hold over 200,000 SKUs of industrial spare parts in stock, and many long-tail models are not listed in full. You can send us an RFQ (Request for Quote) directly, and we will provide wholesale pricing promptly.

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