SRS Labs CTC100, Руководство пользователя

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Introduction 11
CTC100 Programmable Temperature Controller
The CTC100 also has eight isolated TTL I/O lines on a 25-pin connector. The pinout of this
connector is compatible with the standard PC parallel port. The TTL lines can be used as inputs or
outputs, but all eight must have the same direction. The pinout follows (the pin numbers are
embossed next to the pins on the D-sub connector):
1 Unconnected
2 D0
3 D1
4 D2
5 D3
6 D4
7 D5
8 D6
9 D7
10 +5V
11 +5V
12 Gnd
13 Unconnected
14 Unconnected
15 Unconnected
16 Unconnected
17 Unconnected
18 Unconnected
19 Gnd
20 Gnd
21 Gnd
22 Gnd
23 Gnd
24 Gnd
25 Gnd
All 25 pins on this connector are electrically isolated from the rest of the CTC100 and are
floating with respect to earth ground. Therefore, to use the digital I/O lines, at least one of the
s must be connected to ground. Alternatively, if the digital I/O lines are configured as
inputs, the value of D0 to D7 can be set by shorting them either to a +5V pin or to a Gnd pin.
The status of the eight digital I/O lines is reported as a single eight-bit integer value. Each I/O
line is assigned an integer value as shown in the following table:
B it
D0
D1
D2
D3
D4
D5
D6
D7
V a lue
1
2
4
8
16
32
64
128
is the sum of the values of all set bits. For example, if only bits D1 and D3 are
set, the CTC100 shows a DIO value of 2 + 8 = 10.
By using background macros, the digital I/O lines can be associated with most functions of the
CTC100. The remote interface provides bitwise operators to set and query the relays and digital
I/O lines.
The DIO lines can also be used to pass a single, 8-bit value into or out of the CTC. The CTC
treats the DIO like any other channel; for example, its value can be plotted or used in a PID
feedback loop.
Virtual channels
The digital I/O card has three virtual channels, which by default are named V1, V2, and V3.
With the help of a macro, these channels can be used to perform simple real-time calculations (such
as determining the average of several inputs) or to plot or log variables such as the setpoint.
Virtual channels can also be used without macros. For example, if the IO type of a virtual
channel is set to annel can follow the value of another channel (see the description of
the Channel.Follow button in the Operation section), and in addition can be modified by applying a
lowpass filter, subtracting a difference channel, taking its derivative with respect to time, or