Next Advance SP1070-M - Manual (Page 52)

NEXT>>>ADVANCE www.nextadvance.com
SP1000 series operator’s manual
Manual SP1000 series 45
Note on USB: If an RS-232 port is not available on your PC, the pump may be operated through a USB to
RS-232 converter cable (available as an accessory, part #CBL-USB232). This cable attaches to the
standard RS-232 to PC cable (part #CBL-PC-PUMP-7). The PC will create a virtual RS-232
communications port that communicates through the USB to RS-232 converter cable. The terminal
emulator can communicate through this virtual port.
11. Logic Interface: TTL Input and Output
NEW ERA PUMP SYSTEMS ™
WWW.SYRINGEPUMP.COM
(631) 249-1392
Farmingdale, NY [email protected]
Figure 2: Rear of Pump
On the rear of the pump is a DB-9 connector, below the ‘TTL-I/O’ label, which is used for TTL I/O. The
logic signals on this connector permit bi-directional control with external equipment.
Control input TTL logic levels must be held steady for a minimum of 100 ms to be recognized. To
minimize the possibility of false signals caused by glitches and ringing, which could be caused by the
closure of mechanical switches, TTL control inputs are firmware filtered. With a sampling period of 50
ms, glitches of less then 100 ms are filtered out.
Edge detection requires the detection of a change in TTL levels. With a minimum of 100 ms to detect a
level, an edge requires a minimum of 200 ms to be detected. Since the next level change can be detected in
100 ms, creating another edge, the maximum edge to edge frequency is 10 Hz.
Edge changes to the ‘Pumping Direction’ and ‘Operational Trigger’ inputs must occur at least 50 ms apart.
Falling edge refers to a logic high to logic low transition. Rising edge refers to a logic low to a logic high
transition. To guarantee recognition of logic levels, voltages on the input lines must be within the
following ranges:
TTL logic low (0): 0 to 1.5 V
logic high (1): 3.5 to 5.25 V
The Vcc and Ground pins, pins 1 and 9, are for logic reference only. To assure proper voltage levels, the
Ground pin should always be connected to the signal ground of a sensing or controlling device that is
attached to any other pin on the TTL I/O connector. The Vcc pin should not be used to source current. The
TTL I/O pins are defined as follows:
Pin
9
Pin
1