Issue
7718 and Expansion Modules
Environment
I/NET Site
Cause
What Expansion Modules come with the 7718 controller? Can those be bought separately? Can the ribbon cable or stand-offs be purchased separately from the P16UI expansion module also referred to as the P16UISO
Resolution
P16UISO 16 Point Universal Input Module 7718 PCU module, 8.6” x 3.4” (21.8 cm x 8.6 cm). Standoff mount. The Sixteen Point Universal Input (P16UI) expansion module provides sixteen universal (analog or contact) inputs. The expansion module card is 3.25"L x 8.60" W (8.25 x21.8 cm). It attaches on top of the 7718 with standoffs supplied with the module. Signals are passed from the P16UI through a ribbon cable type connection between the terminals of the two boards. The input points on the Sixteen Point E16UI Expansion Board occupy point addresses 0100 through 0107 and 0200 through 0207.
Please find the 7718 Expansion board Input testing procedure below. Also here is the Datasheet
Below is the part number from iPortal:
This is the Model numbers and brief description:
Expansion Board Testing Procedure:
7718 Expansion board Input testing
All 8 AIs (TBX1-1,4,7,10 and TBX2-1,4,7,10) come in thru the same analog multiplexer IC U3.
The only components in front of the Mux is a .47uF capacitor on each input and a 100K resistor on each, and then the user plug-in resistors.
I assume reference to TBX1 is associated with 1st input channel on pin 1 and 249 ohm is being plugged in to SIP socket RS3 position A1.
Assuming no other resistors are plugged in to any of the Bx, Cx or Dx positions, there isn't much left that can be wrong.
Get the specifics of what input signal level is causing what count to be seen.
Use M & B of 1 & 0 to report straight counts.
Make voltage measurements on the TBX1-1 and TBX2-1 terminals with signal being injected, and record the counts seen on the HHC, or PC, for a low medium and high level signal.
An external power supply can be used in place of the sensor to easily set a 0V, 2.5V and 4.90V signal input.
We want something less than 5V so we don't get the high end max count of 4095 which can mask a high end + error.
If they don't have a supply, differing values of resistance can be plugged in to positions A1 (pull down) and B1 (pull up) with J10 set to B-C position so the B positions are pulling up to 5V.
1K in A1 position and B1 open produces 0V input. Measure and confirm volts and counts
1K in both A1 and B1 positions produces mid scale of approx 2.500. Measure and confirm volts and counts
10K in A1 and 1K in B1 positions produces high end of approx 4.545V Measure and confirm volts and counts
This can be repeated on TBX2 using resistor positions A5 and B5
The A/D Counts should equal (measured volts / 5 * 4095)
2.500V = 2047 counts
4.545V = 3722 counts
See what the above shows as a possible indication of where something is going awry.
An A/D count that is correct on one input and wrong on another with only the specified resistances plugged in, or no resistances plugged and an external voltage source being used, would suggest a faulty multiplexer chip (on only specific selected channels) or a faulty capacitor.
Return for repair.
