Pepper Computer Modular Computers RS485 - Manual (Page 145)

Digital Modules
08 Jan. 98
SMART I/O User’s Manual
Page 4 - 59 Manual ID 09901, Rev. Index 0500
Downstream the optoisolation part of the circuit, an RC first-
order, low-pass filter converts signals greater than 40 Hz into
logically suitable values before they enter the system’s digital
input.
The LED driver activates the relevant LED when the input
increases to more than 30 V AC.
As previously mentioned, the last channel is capable of issuing
INTx interrupts, when enabled by software. This interrupt will
only be acknowledged under OS-9, if the module is on the
SMART-BASE, or occupies the first slot of the attached
SMART-EXT unit. This channel is manufacturer-set at 40 Hz,
but other frequencies may be catered for. The table below shows
the settings of the solder jumpers for this filter configuration.
4.4.6 Configuration
Although two solder jumpers (J3 and J4) exist on the board, they
should remain at their manufacturer settings unless a user-spe-
cific filter is required, that for instance cuts off at higher fre-
quencies. If a user-specific filter is required, then contact please
PEP Modular Computers for any further advice, and refer to the
diagram of the filtering components shown in figure 4-5.
Table 4-2: Jumper Settings
Jumper Settings Description
J3 1-2
1-3 Standard input filter 40 Hz
Customer-specific input filter
J4 1-2
1-3 Standard input filter 40 Hz
Customer-specific input filter