Syringe Pumps and Dispensers
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Technical Resources | Common Questions

This page contains some of the more frequently asked questions, concerning our syringe pumps. If you have other questions that are not addressed here, please contact us.

  1. How many PSI does the pump generate? (or alternately: How much pressure does the pump generate?)
  2. Is the pump accurate? How do I check my pump for proper calibration?
  3. What do I do if the pump isn't dispensing properly/accurately?
  4. I'm having trouble communicating via the RS-232 port! What do I do?
  5. What is the minimum/maximum flow rate for my pump?
  6. I have a pump that needs repair, but I think I can do the repairs myself. Do you have new spare parts available?

Q. How many PSI does the pump generate? (or alternately: How much pressure does the pump generate?)

A. The KDS-100 can generate up to about 20 pounds of linear force, and the KDS-200 series can generate up to about 40 pounds of linear force. This is not the same as PSI (pounds per square inch) which is an area measurement. The psi is dependent on the application (such as the viscosity of the liquid, presence and amount of capillary tubing, size of the syringe, etc., so it is impossible to estimate the psi without specific details of your application.

For an application where only a syringe is needed, you can use the data below to approximate the psi generated by the force of the pusher block:

KDS200 with a single syringe: Pressure = force 40 lb / syringe cross-sectional area. Example: Calculate pressure for 20 ml syringe where Barrel ID = 20 mm

Pressure Equation

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Q. Is the pump accurate? How do I check my pump for proper calibration?

A. The most accurate way to check the accuracy of the pump is by measuring the travel of the pusher block and comparing it to the calculated travel corresponding to a set volume. By NOT using a syringe and measuring dispense volume, we avoid errors associated with volume measurement and variations in the diameter of the syringe barrel.

For example:

From Π r2 l = vol Where r = internal radius of syringe barrel, l = length or travel of pusher block.

Measurement of the pusher block travel can be made using a micrometer gauge sitting in the syringe holder. Run the pump to make sure the pusher block is fully engaged on the leadscrew and then enter the volume and set the micrometer gauge to zero. Start the pump and when it stops at the set volume the distance moved by the pusher block can be measured.

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Q. What do I do if the pump isn't dispensing properly/accurately?

A. If after running the calibration test, you determine the values are not within requirements or specifications, you should return the pump to the manufacturer for calibration/repair. Generally this involves tightening the belts, replacing worn hardware, etc. More details on repair actions can be found in that section of the KDS Web site.

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Q. I'm having trouble communicating via the RS-232 port! What do I do?

A. Troubleshooting the communications process is a relatively simple matter. The three components of the problem are the pump, the computer, and the cable between the two.

  1. Configure the Pump – Set the pump RS232 settings.
  2. Verify the cable is working properly. You should see "remote" in the display of the pump after you have sent the pump a command from the computer. If not, you should check your cable The pumps use simple three wire communications - ground, transmit, and receive. No flow control. No handshaking.
  3. Configure the program to the same RS232 setup as the pump. We recommend you test the communication by using Hyperterminal in Windows.

RS232 Format

PC with 9-pin connector
  • data IN.............pin 2
  • data OUT............pin 3

PC with 25-pin connector
  • data OUT............pin 2
  • data IN.............pin 3

Verification of RS232 communications using Windows® Terminal/Hyperterminal

Use two Windows® programs to check the interface:

  1. Terminal in Windows® 3.1
  2. Hyperterminal in Windows® 95 & 98, XP

Hyperterminal Settings

In Properties
  • Set to "direct to COM 2" or appropriate COM port number
Configure
  • 9600 data bits/sec (baud rate must be same in pump)
  • 8 data bits
  • none parity
  • 1 stop bits
  • none flow control
Settings
  • terminal key
  • TTY emulation
  • 500 back scroll buffer
  • echo typed
  • 0 time delay (possibly 100 millisecs)
  • 0 character delay (possibly 100 millicecs)

"Terminal" Settings

Terminal Emulation
TTY generic

Terminal Preferences
  • line wrap - checked
  • local echo
  • Sound
  • Column
  • Cursor - block and - Blink
  • Terminal fone - fixedsys 15
  • Translations - none
  • Show scroll bars
  • Use function arrows
  • Buffer lines - 100
Function Keys
  • Key level 1
Text Transfer
  • std flow control
Binary Transfer
  • X modem / CRC
Communications
  • baud rate 9600
  • Data bits 8
  • Stop bits 1
  • Parity none
  • Flow control none
  • Connector "COM 1"

Modem Commands

prefix
  • suffix
Dial + ATDT
  • ----------
Binary

Original
  • ATQOVIE ISO Modem default: Hayes

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Q. What is the minimum/maximum flow rate for my pump?

A. Minimum and maximum flow rates are dependent on the size of the syringe you are using. Flow rates may be found on the specific product page, listed by model number and syringe size.

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Q. Are there spare parts availablefor the KD Scientific Pumps?

A. We strongly recommend that any repairs done to KD Scientific pumps be performed by KD Scientific technicians here at our facility. Typcial spare part numbers are below.

Typical spare part numbers are below.

PART NUMBER ITEM
KDS-100 Series Parts
1000-015 Keypad
1000-006 Drive nut (also called "half-nut")
1000-024 PCB Assy
1000-008 Pusher Block Assy. (contains drive nut)
1000-100 Mechanism Kit (contains leadscrew, syringe holder block, etc)
KDS-200 Series Parts
2000-015 Keypad
2000-006 Drive nut (also called "half-nut")
2000-016 PCB Assy
2000-050 Pusher Block Assy. (contains drive nut)

*Please note: Different KDS-200 series pumps have different pusher block assemblies! Please call for specific requirements!

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