907-420 (6-Channel 4-20 Ma Card); Figure 5-11: 907-420 Expansion Card - Focal 907 User Manual

907-0601-00 Rev. C

5.11 907-420 (6-Channel 4-20 mA Card)

Card P/N
Config. Dwg.
Diagnostics:
The 907-420 expansion card shown in Figure 5-11 is used to multiplex up to six channels of 4-20 mA inputs.
The 4-20 mA input signal is a current-based signaling scheme where 4 mA represents zero percent signal
and 20 mA represents the one hundred percent signal. The input current levels are converted to voltages and
an ADC is used to digitize the signal. The card is factory configured for 12-bit digitization of the 4-20 mA
signals at a sample rate of 30 Hz.
The multiplexed channels from this card are not available on the PC/104 backplane connector but are instead
provided at two RS-232 channels on connector J2. The RS-232 serial stream must therefore be connected to
an available RS-232 input/output connector on another 907 card. Alternatively, the 907-420 may be installed
on a Eurocard adaptor for use in a Model 903 system, in which case the RS-232 output must be harnessed to
an available RS-232 channel at the front panel.
For output, the card supports two output RS-232 channels which contain the digital representation of the six
input channels of multiplexed input data streams. Details of the RS-232 format are provided in the
configuration drawing.
Focal Technologies Corp.
907-0218-01
907-2024-00
None

Figure 5-11: 907-420 Expansion Card

Model 907 Video/Data Multiplexer – User's Guide
Page 5-13